AAMC practice exam 4 Question and answer 100% solved 2023

AAMC practice exam 4 Question and answer 100% solved 2023Limestone does NOT decompose when heated to 900 K because, at 900 K, ΔH is: *The chemist placed a sample of limestone, CaCO3(s), into a sealed chamber and then heated the limestone to 1200 K to generate CO2(g) and CaO(s). A. positive and less than TΔS. B. positive and greater than TΔS. C. negative and less than TΔS. D. negative and greater than TΔS. A. positive and less than TΔS. think about it, if H is positive and less than TS than G is positive and the reaction is non spontaneous. that is why it won't decompose at 900K, need more heat When limestone is heated during Step 1, an equilibrium is established. Which of the following expressions is the equilibrium constant for the decomposition of limestone? **The chemist placed a sample of limestone, CaCO3(s), into a sealed chamber and then heated the limestone to 1200 K to generate CO2(g) and CaO(s). A. [CaO] B. [CaCO3] C. [CO2] D. [CaO] × [CaCO3] C. [CO2] SOLIDS ARE EXCLUDED FROM EQUILIBRIUM RXNS CaCO3(s) --->CO2(g) + CaO(s) products/reactant, no solids, so only Co2 is the answer During Reaction 2, did the oxidation state of N change? **NH3(aq) + CO2(aq) + H2O(l) → NH4+(aq) + HCO3-(aq) A. Yes; it changed from -3 to -4. B. Yes; it changed from 0 to +1. C. No; it remained at -3. D. No; it remained at +1. C. No; it remained at -3. this is an acid-based reaction, which does not involve the oxidation state changes. The part of Reaction 2 that involves nitrogen is the protonation of ammonia (NH3 + H+ →NH4+). Acid-base reactions do not involve oxidation state changes. The oxidation state of N in NH3 is -3. Each H is +1 and is balanced by the -3 of N to make a neutral compound. The oxidation state of N does not change when the N is protonated. What is the approximate energy of a photon in the absorbed radiation that yielded the data in Table 1? (Note: Use 1 eV = 1.6 × 10-19 J and hc = 19.8 × 10-26 J•m.) ***Measurements made in the entire visible spectrum showed that absorbance occurred only at wavelength 625 ± 5.0 nm according to the data in Table 1. A. 1 eV B. 2 eV C. 3 eV D. 4 eV C. 3 eV 19.8 × 10-26 J•m./ 625*10^-9= 3.1 × 10-19 J ≅ 2 eV. #7. According to Table 1, what is the concentration of the glucose in the blood from which the diluted sample was taken? **In a test, a blood sample with 1/30 dilution ratio was mixed in a transparent cuvette with an oxygen-acceptor solution containing glucose oxidase. ** you can see on the chart that the absorbance goes from 0.20 to 0.24 and the glucose concentration is 6mg/dL at 0.24 A. 60 mg/dL B. 90 mg/dL C. 120 mg/dL D. 150 mg/dL D. 150 mg/dL to solve this, you can set up a proportion. (0.20/0.24)*6mg/dL= 5.0mg/dL to get the concentration of the glucose in the blood from which the diluted sample was taken, multiply 5*30= 150mg/dL Suppose a blood sample tested above the range (6.0 mg/dL) of the standards used in the experiment. What modification will provide a more precise reading by data interpolation as opposed to extrapolation using the same standards? A.Increase the enzyme concentration. B.Increase the oxygen pressure. C.Decrease the content of oxygen acceptor. D.Dilute the sample with additional solvent D.Dilute the sample with additional solvent Interpolation - prediction based on existing data (i.e. between given data points) Extrapolation - is an educated guess beyond the existing data points By adding solvent, the concentration of glucose will be lowered, and the resulting absorbance will fall within the range of the standards. This is easily accomplished, and the resulting calculations that account for the dilution are not difficult. picked c- glucose IS the oxygen acceptor so changing that will defy the whole experiment What is the frequency of the pulses that deliver laser radiation to the cornea? **Material in excess is removed by vaporization from the surface of the cornea with the use of pulsed laser radiation at time intervals of 250 ms. A. 0.4 Hz B. 4.0 Hz C. 25 Hz D. 250 Hz B. 4.0 Hz Frequency is v/wavelength but also can be F=1/time 1/250ms 1/.250s= 4 Hz NH3 acts as a weak base in water with Kb = 1.76 × 10-5 at 25°C. The corresponding equilibrium is shown below. NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq) At 25°C, the equilibrium concentration of the NH4+ ion in a 10 M aqueous solution of NH3 would be closest to which of the following? A. 0.001 M B. 0.01 M C. 0.1 M D. 1 M B.0.01 M know that this is an equilibrium problem and that the products and reactnat s are a 1:1 ratio. so the answer is the sqrt of 1.76 × 10-5 which is 0.01 quick maths square the exponent sqrt10^-4 = 10^-2= .01 What is the concentration of the acute leukemia CC95 Combination value in micromolar (μM) units? **0.6nM A. 6 × 10-10 μM B. 6 × 10-7 μM C. 6 × 10- 4 μM D. 6 × 10-2 μM C.6 × 10- 4 μM 0.6x10^-9/0.610^-6= 0.610-3= 6*10^-4 REALIZE WHEN THE ANSWER CHOICES ARE A DECIMAL OFF AND CHANGE THE EXPONENTS TO MATCH 0.6 to 6---> add another exponent 10^-3 to 10^-4 Which of the following functional groups is present in pyrrolizidine (Figure 1)? A. An amide B. An amine C. An imine D. A carbamate B. An amine